Differentiation and growth of the embryonic nose, lens and corneal anlagen implanted into the larval eye or dorsal fin in <i>Amblystoma punctatum</i>

Reyer, Randall W.

doi:10.1002/jez.1401510204

Cited by 33 publications

(2 citation statements)

References 53 publications

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“…REYER (1962bREYER ( , 1966a implanted lens vesicles, removed from the eyes of Ambystoma maculatum or N otophthalmus viridescens embryos, into the larval dorsal fin or into the anterior chamber or vitreous chamber of the larval eye either with the host lens present or after lentectomy. REYER (1962bREYER ( , 1966a implanted lens vesicles, removed from the eyes of Ambystoma maculatum or N otophthalmus viridescens embryos, into the larval dorsal fin or into the anterior chamber or vitreous chamber of the larval eye either with the host lens present or after lentectomy.…”

Section: Lens Induction and Cytodifferentiationmentioning

confidence: 99%

The Amphibian Eye: Development and Regeneration

Reyer

1977

The Visual System in Vertebrates

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Section: Lens Induction and Cytodifferentiationmentioning

confidence: 99%

The Amphibian Eye: Development and Regeneration

Reyer

1977

The Visual System in Vertebrates

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“…This suggests that in a minority of cases, a few cells in 3-to 4-somite stage opV ectoderm are committed to Pax3 expression, correlating with the limited neurofilament staining in a few cells in a minority of the explants. However, this early commitment of a few cells to Pax3 expression, while observed in vivo, may not have been supported in our explant conditions (similar results were obtained in studies on amphibian placode induction; Reyer, 1962). In older explants, In 5-to 7-somite stage explants, 45% contained a limited amount of neurofilament staining and occasional process-bearing neurons, while 40% contained a few (<10) Pax3-positive cells (n=40).…”

Section: Pax3 Expression Correlates With Neuronal Specification In Opv Ectodermmentioning

confidence: 47%

Establishing neuronal identity in vertebrate neurogenic placodes

Baker

Bronner‐Fraser

2000

Development

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The trigeminal and epibranchial placodes of vertebrate embryos form different types of sensory neurons. The trigeminal placodes form cutaneous sensory neurons that innervate the face and jaws, while the epibranchial placodes (geniculate, petrosal and nodose) form visceral sensory neurons that innervate taste buds and visceral organs. In the chick embryo, the ophthalmic trigeminal (opV) placode expresses the paired homeodomain transcription factor Pax3 from very early stages, while the epibranchial placodes express Pax2. Here, we show that Pax3 expression in explanted opV placode ectoderm correlates at the single cell level with neuronal specification and with commitment to an opV fate. When opV (trigeminal) ectoderm is grafted in place of the nodose (epibranchial) placode, Pax3-expressing cells form Pax3-positive neurons on the same schedule as in the opV placode. In contrast, Pax3-negative cells in the grafted ectoderm are induced to express the epibranchial placode marker Pax2 and form neurons in the nodose ganglion that express the epibranchial neuron marker Phox2a on the same schedule as host nodose neurons. They also project neurites along central and peripheral nodose neurite pathways and survive until well after the main period of cell death in the nodose ganglion. The older the opV ectoderm is at the time of grafting, the more Pax3-positive cells it contains and the more committed it is to an opV fate. Our results suggest that, within the neurogenic placodes, there does not appear to be a two-step induction of ‘generic’ neurons followed by specification of the neuron to a particular fate. Instead, there seems to be a one-step induction in which neuronal subtype identity is coupled to neuronal differentiation.

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Lens regeneration from the cornea in Xenopus laevis

1963

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Developmental problems relating to the stability of cell phenotype, and to the interactions between cells during morphogenesis can be approached particularly well through the study of regenerating systems. In the case of lens regeneration the anatomy of the eye is such that it is possible to identify the tissue types that can form lens, and to analyze the role of the factors which control the regenerative process. At present, it has been established that the lens can regenerate from the iris (Stone, '59; Reyer, '54, '62); and there is some evidence that the lens can regenerate from the cornea (Reyer, '54).The most convincing evidence for lens regeneration from the cornea has been provided by Ikeda ('36, '39) for late embryonic and early larval stages of Hynobius unnangso. In this series of experiments, the lens anlage with the surrounding ectoderm was removed from embryonic animals and head ectoderm was allowed to heal over the eye cup. A histological study of these animals showed various stages of lens formation from the ectoderm over the eye cup, but a complete series of stages showing the process of lens regeneration was not presented. The time during which lens regeneration could take place was limited to a short period of embryonic life after lens induction. These results were complicated by the claim that lens regeneration from the iris takes place during the same time period (Ikeda, '37). In the second experiment in this series pieces of prospective and differentiating cornea from animals at different developmental stages were implanted into the eye cup of young animals after lens removal. Here lens formation was observed from the inner cell layer of the epithelial component of the cornea. The portion of the corneal epithelium which did not contribute to the lens usually developed into epidermis. This paper describes lens regeneration from the cornea in another species, XenoUniversity of Chicago, Illinois p u s laevis. The study was made on three different larval stages, and young metamorphosed animals. With this material the process of lens regeneration was studied histologically, the growth of the lens was plotted, and the competence of the eye to regenerate a lens at different developmental stages was measured. A cytological analysis was then made of the changes in the behavior of the nucleolus that take place during regeneration.This description of lens regeneration was supplemented by experiments designed to verify the observation that the cornea forms lens. This was done with extirpation and grafting experiments, in some of which tritiated thymidine was used as a marker.Two factors which control the process of lens regeneration were also studied. The role of the optic cup was studied by testing for lens regeneration in its absence. The limitation of regenerative capacity to the larval eye was studied by local application of thyroxin.A preliminary account of this work has been published (Overton and Freeman, '60; Freeman and Overton, '61, '62). MATERIALS AND METHODS AnimalsThe animals used for the e...

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Differentiation and growth of the embryonic nose, lens and corneal anlagen implanted into the larval eye or dorsal fin in Amblystoma punctatum

Cited by 33 publications

References 53 publications

The Amphibian Eye: Development and Regeneration

The Amphibian Eye: Development and Regeneration

Establishing neuronal identity in vertebrate neurogenic placodes

Lens regeneration from the cornea in Xenopus laevis

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